The invention relates to a restraining device comprising an air bag, a controller controlling the ignition time and/or the fill of the air bag, and responsive to sensor signals characterizing the position of a vehicle occupant from at least one sensor element. The sensor signals suppress the release of the air bag if the controller, on the basis of the sensor signals, identifies a critical position of the occupant in a xe2x80x9cdangerxe2x80x9d zone of the air bag.
In know arrangements provision is made so that the controller evaluates the sensor signals characterizing the sitting position of the occupant, particularly whether the occupant is in a previously defined danger zone, determined substantially by the range of swing of an air bag flap normally covering the air bag, and an additional, more extensive range determined essentially by the deploying characteristic of the air bag. In that case, the controller of the known arrangement device assumes that in event of a release of the air bag taking place at this time, the occupant would be seriously endangered, and therefore generates a control signal inhibiting the release of the air bag.
This procedure has the disadvantage that the controller reacts statically to the pre-defined values of the danger zone and therefore not flexibly enough to the actual process of the accident.
It is an object of the invention to provide a restraining device that provides adaptation of the control signal of the controller to suppresses release of the air bag according to actual conditions.
According to the invention, the controller of a restraining device defines a danger zone dynamically, as a function of parameters supplied to it from one or more sensors.
The arrangement according to the invention has the advantage that there is provided a better adaptation of the release behavior of the air bag to the actual process of the accident. In the case of accidents of minor severityxe2x80x94as an example of a parameter external to the vehiclexe2x80x94provision is advantageously made so that the controller bases its decision whether to generate a control signal inhibiting release of the air bag or not on, a larger danger zone, whereas with a greater severity of accident, this decision is based on a dynamic danger zone substantially smaller than the pre-defined static danger zone; that is, in the case of the restraining device according to the invention, in the case last mentioned, the air bag is also released if the occupant of the vehicle is in an xe2x80x9cout-of-positionxe2x80x9d attitude or even in a xe2x80x9ccritical out-of-positionxe2x80x9d attitude.
An advantageous refinement of the invention provides that the weight of the occupantxe2x80x94that is, a parameter internal to the vehiclexe2x80x94is sensed, and a corresponding sensor signal is supplied to the controller of the restraining device according to the invention, and incorporated in the calculation of the dynamic danger zone.
Another advantageous refinement of the invention provides that the speed of the vehicle and/or the acceleration of the vehicle is incorporated in the calculation of the dynamic danger zone. According to further advantageous refinements of the invention, provision may advantageously be made so that the direction of motion and/or the place of impact of the occupant are incorporated in the determination of the dynamic danger zone.
Other details and advantages of the invention will be found in the embodiment about to be described by way of example with reference to the figure.